Various analytical instruments have been developed for making optics-based measurements (e.g., fluorescence, luminescence, absorbance, microscopy, etc.) on samples (e.g., chemical compounds, biological material, etc.) as part of assays useful in the life science industry. Many analytical instruments are designed to carry out only one or a few dedicated types of measurements. On the other hand, multimode analytical instruments, also referred to as multimode readers, are designed to perform multiple analytical assays in a single instrument. Multimode analytical instruments may be designed to be re-configurable to enable a user to select different types of measurements to be performed. Some multimode analytical instruments utilize application-specific cartridges to enable re-configuration. The samples analyzed or measured by an analytical instrument typically supported in a multi-well microtiter plate (also known as microplate or optical plate), although other types of sample holders or containers may be utilized. The microplate containing the samples is typically loaded into the interior of the analytical instrument, and the interior is isolated from the ambient to enable optical-based measurement or imaging to be performed.
Depending on the type(s) of analysis an analytical instrument is capable of performing on a sample, the analytical instrument may include various types of movable components, such as fluidic components (e.g., nozzles, pipettes, etc.), optical components (e.g., lenses, etc.), and mechanical components (e.g., motorized stages, microtiter plate transports, etc.) that operate in the closed interior of the analytical instrument. It would be desirable to be able to monitor these movable components, including determining the presence and position of such components.